The delivery of a drug to a desired location in the body has always posed a number of problems. The objective is normally to deposit the drug in a region, such as a specific organ, where the drug can benefit the intended organ and limit the delivery of the drug to other areas where the drug does no good or may actually produce undesired side effects.
This situation prevails particularly when administering medicine orally wherein the medicine must first pass through the alimentary tract before reaching the intended target. The result is that medicine is thereby deposited throughout the entire body which may result in side effects and may result in having to administer a much larger dose than would otherwise be required if the drug were delivered to a localized region.
One method for delivering the drug is by directing a spray to the underside of the tongue which is a particularly appropriate area for absorbing the medication directly into the bloodstream thereby avoiding the necessity to pass through the alimentary canal.
Another method of administering medication is through a tube (hypodermic needle) where the point of the needle is inserted under the skin. This method is used in a wide variety of situations such as for administering nutrients (intravenous feeding) and vaccines. The use of the hypodermic needle is very effective for placing the drug in a location which is close to the skin (e.g., intravenous feeding) but when used for depositing in deep lying organs, the positioning of the tip of needle is hit or miss and cannot be counted on to place the medication at an exact location unless the location is first exposed by a surgical procedure. Of course, any surgical procedure is accompanied by a degree of trauma.
Recently, a new electrochemotherpay (ECT) anti tumor treatment has been developed, which treatment consists of locally delivering shocks of high intensity electric pulses to tumor sites a short time after the systemic administration of chemotherapy. The DC electrical pulses open large transient pores in the plasma membranes of the exposed cells.
The electrochemotherapeutic agents can enter the cells through the pores resulting in locally enhanced cytotoxicity.
U.S. Pat. No. 5,386,837 to Sterzer discloses the use of force fields for enhancing delivery of chemotherapy. The general approach is to apply the medicine in an area adjacent the intended area (e.g., a tumor) and then to apply a "force" field which opens up transient pores in the plasma membranes of the targeted cells. The Sterzer patent discloses the use of any one of electromagnetic, laser or ultrasound waves to practice the invention.
The use of ultrasound imaging has become an important technology for examining soft tissue of the body and has become particularly widely used to provide direct real time examination of the cardiovascular system. The technology includes methods for presenting on a video monitor views of cross sections ("slices") showing movements that occur in these slices. Ultrasound imaging technology involves the use of a planar array of piezoelectric transducers wherein each transducer emits an ultrasonic wave having a phase relative to other members of the array such that a directed beam is radiated from the array and is programmed to "scan" an entire region of interest. The scanning beam is reflected by the target region and the intensity of the reflected beam which varies as the beam scans the entire region is stored in memory and used to create a visual image of the scanned area on a monitor screen.
U.S. Pat. No. 4,581,636 to Blaker discloses "B slice" scanners which includes a digital scan converter to change echo data stored in digital memory into television format. (A "B-slice" is a planar section of an organ of the body wherein the plane of the slice intersects the source of the ultrasonic beam.) The scan converter includes a frame buffer memory wherein each address is identified by variables u, v, the coordinates of the corresponding location on the display screen. When memory location u,v is addressed, the coordinate values u, v are transformed to a pointer vector in object space which is used to address a location in memory where ultrasonic intensity data corresponding to the location in object space has been stored and this intensity data is then presented as visual intensity at location u,v on the monitor screen. The image on the display screen is refreshed typically every 1/30 sec.